Independent Research Project Need Help

I am in a senior level scientific measurements using digital interfacing class, which is basically like a smash-up of digital circuits lab, intro to DAQ and DAC/ADC, and senior project. Now, part of this class, only 10%, is a independent "research" project. I put this in quotes because we only have half a semester to do this project.

I don't know if anyone else has had any project like this, but I am having a really hard time finding a medium between too hard and too easy. I don't want this class to eat up all my time, but I want to do something interesting and challenging.

The project needs to be a physical circuit that implements a theory or idea and is somewhat digital.